For the potato roast peel potatoes and grate coarsely. Salt and pepper, beat in the eggs and mix well.
Fry the roast mixture in portions, flattened, in hot fat for 5 minutes on each side. Mix crème fraîche with zest and 5 tablespoons juice of oranges, chopped tarragon leaves and some chives.
Arrange the potato roasts on plates, top with tarragon orange sauce and smoked salmon and garnish with tarragon leaves.